how do we overcome the resistance from people who oppose progress because of their monetary interest in keeping existing systems dominant. If that were easy, we'd be flying amongst the stars already.

Venture capitalism can be a good thing, with a little help from the goverment.

-Laelth

and so do rooftops covered with soil and plants.

One of the biggest wastes of electricity is the inefficient air conditioning of buildings, particularly large commercial and industrial structures. Triple-pane windows can do a lot, and reflective white roof coating is another energy saver.

White roofs can save up to 15% in energy costs.
http://www.environmentalleader.com/2010/07/20/white-roofs-can-save-15-on-energy-costs/

When we replaced the roof on our house a couple of years ago, we went with white shingles that had a certain amount of reflectivity and were EPA Energy Star approved. The roofer put in a ridge vent and soffit vents to keep the attic cooler during the summer. It's hard to tell with the nonstop price increases by our electric utility, but our summer cooling bills seem to be lower, and the ceilings right under the attic no longer feel hot to touch on warm days.

The reason is simple, what you gain in Summer with reduced heat, is lost in Winter, again due to loss of heat. Thus black has always been the color of choice when it comes to roof in most northern areas (it also helps that if you can venilate the roof in the summer, the heat goes elsewhere then in the house. thus in Winter, when you shut up the windows the black roof absorb sunlight and heats up the house).

Notice the above assumes no Air Conditioning, again charteristic of Northern Climates.

On the other hand, gardens on roof are a huge plus. It is like trees around a farm house. In winter the trees have no leaves and the Sun's light rasy hit the windows and roof on the house directly, helping to warm it up. In Summer, the trees have leaves and thus block the sun light from reaching the house Roof or Windows.

Roof Gardens can be similar, during the summer covered by various plants that absorb the sun light before it hits the roof. During Winter, the plants are either dead or dormant and thus the sunlight can heat up the dark dirt that in turn can heat the building.

Now, again both of the above is more common in Northern Climates then Southern Climates. As you go south, winter is shorter and the issue is the heat of the day (and the heat of the noon time sun was why most people living in southern climates tend to have "Siestas", more to avoid doing anything during the heat of the day then anything else. In a recent study, workers in Spain where such breaks are common, where as efficient workers as German Workers who do not. The reason being Germany is that much further North, so noon time heat is NOT that bad, and thus culurally they work right through it. On the other hand the Spainish worked in the Morning, and then in the Evening, for those two time period permitted them to avoid working in the heat of the day. Both were as efficient on a per hour basis, something the authors of the Study did not expect, but fell right out of the study.

Another factor is as you go south, The shortest winter daylight hours are NOT as short as further North. Thus a German may have to work eight straight hours to be able to go to and from work in daylight in winter. That is less a concern for a worker in Spain, since his winter daylight hours are longer then one further to the north (and the reverse is also true, a Worker in Spain had less SUMMER daylight hours at the height of Summer then does a Worker in Germany).

For some example look at the US Navy Time observations:
http://aa.usno.navy.mil/data/docs/Dur_OneYear.php

Brownsville Texas has only 10 hours and 31 minites of daylight in Decemer 21
http://aa.usno.navy.mil/cgi-bin/aa_durtablew.pl

St Paul Minnisota daylight on December 21st is only 8 hours, 46 minutes, almost 2 hours less daylight on the same day:
http://aa.usno.navy.mil/cgi-bin/aa_durtablew.pl

Thus you could take a two hour Siesta in Brownsville and still get in an eight hour work day, while you could NOT do that in St Paul if you only could work during daylight.

That black roofs get you any solar gain in the winter in cold climates. Think about it: if you have the requisite R-50 of insulation (that's what's recommended up here in Minnesota) and proper air-sealing, very little heat will be transferred in EITHER direction from the home's interior. In that case, a white roof won't be a detriment a home's heating load in winter.

The only real problem I could foresee is that, in very snowy climates, the snow might not melt rapidly enough to prevent roof collapse from the added weight.